Gear type air pump with changespeed gearing and lubrication



July 26, 1949. I w. w. PAGET 2,477,002

GEAR TYPE AIR PUMP WITH CHANGE-SPEED GEARING AHD LUBRIQATION Filed' July 25, 1942 '7 Sheets-Sheet 1 Juiy 26, 1949. w. w. PAGET "i fi GEAR TYPE AIR PUMP WITH CHANGE-SPEED v GEARING AND LUBRICATION Filed July 25, 1942 7 Sheets-Sheet July 26, 1.949. w. w. PAGET 2,477,002

GEAR TYPE AIR PUMP WITH CHANGE-SPEED GEARING AND LUBRICATION- 7 Shqets-Sheet 3 Filed July 25, 1942 y y 1949- w. w. PAGE T 2,477,002

GEAR TYPE AIR PUMP WITH CHANGE-SPEED GEARING AND LUBRICATION Filed July 25, 1942 '7 Sheets-Sheet 4 ,liiaMmmnummxmmMW MA'MQ.

July 26, 1949. w w, -r 2,477,002

GEAR TYPE AIR PUMP WITH CHANGE-SPEED GEARING AND LUBRICATION Filed July 2 55, 1942 7 Sheets-Sheet 5 Eigdg. 3} 297 303 305 fizven fir: Zl/t'n Z0! Paget.

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July 26, 1949. w. w. PAGET GEAR TYPE AIR PUMP WITH CHANGE-SPEED GEARING AND LUBRICATION '7 Sheets-Sheet '7 Filed July 25, 1942- uw/ alor: 'n ll]. Pa gat.

Patented July 26, 1949 GEAR TYPE AIR PUMP WITH CHANGE- SPEED GEARING AND LUBRICATION Win W. Paget, Michigan City, lnd., assignor to Joy Manufacturing Company, a corporation of Pennsylvania Application July 25, 1942, Serial No. 452,299

6 Claims. 1

My invention relates to air pumping apparatus, and more particularly to apparatus for the maintenance of adequate pressure conditions in the cabins or other passenger compartments of airplanes which are adapted to be operated at widely varying altitudes, including high altitudes.

As is well known, it is necessary or at least highly desirable, in order that a plane may obtain the advantages of high altitude flight, to make special provision for the safety and comfort of the pilot and/or passengers. For this purpose supercharged cabins and other passenger compartments present particular advantages. While a mere displacement pump may serve Satisfactorily under certain ranges of altitude as an air delivery device for a cabin or other compartment, a pump capable of the actual compression of air is more satisfactory for high altitude flight. It is desirable, in the provision of a pumping apparatus of the compressor type, to provide a pump which shall have a large displacement in small compass, which shall be able actually to compress the air taken in through one or more compressions prior to discharge; to provide a pump which at many altitudes shall avoid the consumption of unnecessary power and the needless generation of heat by operating as, or substantially as, a mere air displacement device; to provide a pump whose speed of operation shall be automatically varied in accordance with predetermined changes in engine speed; to provide a pump which shall automatically change its characteristics from a simple air displacement apparatus to a true compressor when certain conditions obtain, such as, for example, the elevation of the apparatus to a height where the external pressure falls below a predetermined value; and to provide a pump in which, notwithstanding the automatic control of speed of operation, deliberate manual control of speed is possible.

It is an object of my invention to provide an improved gaseous fluid pumping apparatus. It

is another object of my invention to provide an improved gaseous fluid pumping apparatus having'an improvedautomatic speed control means. It is a further object of my invention to provide an improved gaseous fluid pumping apparatus having improved hydraulic speed-responsive mechanism for automatically changing the efiective driving gearing therefore when the same is driven at certain predetermined speeds. It is yet another object of my invention to provide an improved gaseous fluid pumping apparatus having improved unloading means. It is still another object of my invention to provide a gaseous fluid pumping apparatus having improved controlling means for governing the operation thereof in accordance with intake pressure variations. It is still another object of my invention to provide an improved gaseous fluid pumping apparatus having improved controlling means therefor including fluid operated, speed-changing driving gearing and fluid operated unloading means both operable by a common operating medium. It is still another object of my invention to provide an improved gaseous fluid pumping apparatus of therotary type having improved unloading means. It is still a further object of my invention to provide an improved gaseous fluid pumping apparatus having improved means for lubricating the same. A further object of the invention is to provide improved gaseous fiuid pumping apparatus having improved governing means. Another object is to provide a compressor having improved speed control means operative to efiect a reduction in the speed of the compressor when the compressor speed reaches a predetermined value. Still another object is to provide a compressor connected through drive gearing to power means and having improved control means operative at a predetermined compressor speed for changing the drive gearing to effect a slower driving of the conipre'ssor. Yet another object of my invention is to provide a compressor having improved means operating at a predetermined low intake pressure for effecting an increase in the pump discharge pressure. Other objects and advantages of the invention .will hereinafter more fully appear.

In a preferred embodiment of my invention, a pair of intermeshing rotors may be supported within a casing and operate when driven to de liver air from an intake at one point in the casing to a discharge port at another point in the casing. The rotors may desirably be provided at one end with shafts having gears mounted thereon for transmitting power from a drive shaft to the rotors and for maintaining the rotors out of contact with each other-but in such close relation that space packing is provided. A pair of the gears may be alternatively connected in driven relation to the drive shaft for eflecting drive of the rotors at difierent speeds. Desirably, there may be connected to rotate with one of the rotors a speed responsive device'for governing a valve mechanism for controlling the flow of an operating fluid relative to a fluid actuated clutch mechanism which is operable to connect one of the two gears last mentioned in driven relation with respect to the drive shaft. At comparatively low rotor speeds, such valve device may desirably perate to supply fluid to the clutch mechanism in such a manner as to effect a connection of that gear which drives the compressor through a high speed gear ratio. When the rotor speeds reach a predetermined value, the speed responsive device desirably operates to vent fluid from the clutch operating mechanism thereby to disconnect the high speed gear and to permit drive to be transmitted through the other of said pair of gears to the rotors. Desirably, manually operated valve means are included for removing the control'ol.

the fluid flow from the speed responsive device operated valve and for controlling directly the flow of fluid relative to the clutch mechanism at will. Further, there is desirably associated with the compressor a control mechanism operative when the compressor intake pressure is above a predetermined value to effect compressor discharge at a relatively low pressure, and in a preferred form, without any compression, while upon a predetermined decrease in the intake pressure the control means operates to preclude discharge by the compressor without a substantial compression of the fluid taken into the same. Desirably, such control device may take the form of a valve mechanism for controlling an auxiliary discharge opening arranged in such relation to the casing that the same has communication with the rotor pockets well prior to the attainment of said pockets to the normal discharge opening, and a valve device for controlling such opening. Advantageously the valve device may be controlled by lubricant pressure provided by the lubricating system of the compressor.

Further in the preferred embodiment there may be a common hydraulic system for the speed control and compressor discharge pressure control mechanisms of the compressor unit, such hydraulic system preferably utilizing the lubricant of the compressor whereby a single pump may supply pressure for operating change speed gearing and valve mechanism for controlling the compressor delivery pressure and supply the lubricant to the lubricated portions of the compressor.

In the accompanying drawings there are shown for purposes of illustration one form and a modification which the invention may assume in practice.

In these drawings,

Fig. 1 is a side elevation of the complete apparatus.

Fig. 2 is an end elevation of the apparatus of Fig. 1, viewed from the left-hand end of Fig. 1 and showing the drive end of the apparatus.

Fig. 3 is an opposite end elevation of the apparatus shown in Fig. 1, being an illustration of the right-hand end thereof.

Fig. 4 is an enlarged .central longitudinal vertical section on the plane of the line 4-4 of Fig. 2.

Fig. 5 is an enlarged horizontal fragmentary sectional view on the plane of the line 5--5 of Fig. 3, showing a detail of the hydraulic system.

Fig. 6 is a horizontal longitudinal sectional view on the planes of the line 6-6 of Fig. 4, with parts shown in elevation.

Fig. 7 is a view showing portions of the unloading mechanism shown in Fig. 6 in difierent positions and with certain additional parts shown in elevation.

Fig. 8 is a vertical sectional view on the plane of the line I--8 of Fig. 6, with parts shown in full.

Fig. 9 is a vertical transverse sectional view on the plane of the line 9-9 of Fig. 6, showing a detail of construction of the unloading mechanism.

Fig. 10 is an enlarged fragmentary sectional view showing venting means for the unloading valve operating cylinder, the view being taken substantially on the plane of the line l0|0 of Fig. 1.

Fig. 11 is an enlarged horizontal sectional view through the control mechanism at the right-hand end of the apparatus, the view being taken on the same plane as Fig. 6.

Fig. 12 is a fragmentary sectional transverse section on the plane of the line I2l2 of Fig. 11, showing a manually operable control valve positionable to vary the speed of drive of the pumping apparatus.

Fig. 13 is a section on the lines l3| 3 of Fig. 12.

Fig. 14- is an enlarged detail sectional view on the axis of the speed-responsive device for controlling the speed of drive of the apparatus.

Fig. 15 is a transverse vertical sectional view taken on the plane of the line l5--l 5 of Fig. 14.

Fig- 16 is a fragmentary view generally similar to Fig. 14 but with parts shown in elevation and illustrating a different position of the parts.

Fig. 17 is a detail longitudinal sectional view on the plane of the line l'l-Il of Fig. 15.

Fig. 18 is a fragmentary detail view showing a locking screw for the governor.

Fig. 19 is an enlarged horizontal sectional view on the same plane as Fig. 6, showing details of construction of the external pressure-responsive unloader valve controlling pilot mechanism.

Fig. 20 is a fragmentary view on the same plane as Fig. 19, showing the parts in different relative positions.

Fig. 21 is an enlarged transverse vertical section on the plane of the line 2I-2I of Fig. 4.

Fig. 22 is a longitudinal view on the line 22-22 of Fig; 21.

Fig. 23 is an enlarged fragmentary sectional view on the plane of Fig. 4, showing details of the speed-controlling drive clutch.

Fig 24 is a vertical sectional view on the plane of the'line 24-24 of Fig. 4, showing a portion of the driving gearing.

Fig. 25 is an enlarged transverse fragmentary sectional view showing a detail of the drive mechanism.

Fig. 26 is a fragmentary section on the plane of the line 26--26 of Fig. 25, showing a detail of a roller ratchet.

Fig. 27 is a section on the line 2'I21 of Fig. 25, showing another detail of the roller ratchet mechanism.

Fig. 28 is a vertical sectional view on the plane of the line 28-28 of Fig. 6, showing the high pressure head of the pump.

Fig. 29 is a vertical transverse section on plane of the line 29-29 of Fig. 4.

Fig. 30 is a similar view showing a modification.

In the preferred embodiment of the invention shown, the pumping apparatus, generally desigthe nated C, comprises a main casing part 3| and a pair of coacting rotors 32 and 33. The rotor 32 is a male rotor and comprises four helically arranged lobes 34, the rearward sides 33 of which are shown as generated curves in profile, while the leading or pressure side 38 of each of these lobes is, in profile, substantially in the 'form of a circular arc. The female rotor 33 is provided, in the form shown, with six helically arranged grooves 31 each adapted to cooperate with the lobes of the rotor 32, and the leading concave surfaces 33 of the grooves 31 are in profile substantially in the shape of an arc to coact with the arcuate pressure surfaces 33 of the lobes of the rotor 32, while the following concave surfaces 33 of the grooves 31 are generated curves in profile. It will be understood that with a device ofthis character, a materially shortened sealing line is had for the pockets or. working spaces which are formed by the coaction of the rotors with each other. A different form of rotor construction maybe used without departing from various aspects of my invention, as for example that construction which is shown in Fig. 30, in which the rotors 32' and 33' have their respective lobes 3 4 and grooves 31' formed with generated surfaces in a well known manner. With rotors constructed and arranged as illustrated, it will be evident that they will have, as it were, low pressure and high pressure ends.

In either case, the rotors are adapted to operate with space packing; that is to say, they are maintained in such relation to each other, through gearing, that there is no actual contact between the rotors with each other. Eachof the rotors 32, 33 is herein shown supported at its ends by stub shafts, the rotor 32 having a stub shaft 43 at its low pressure end and a stub shaft 4| at its high pressure end; while the rotor 33 has a stub shaft 42 at its low pressure end and a stub shaft 43 at its high pressure end. The stub shafts 43 and 42 are supported in suitable bearing sleeves 44 and 45 supported in bores 46, 41 in an integral end casing portion 48 formed in one piece, as herein shown, with the housing 3 I. A separate, pluralpart head 53 supports ball thrust bearings 5| and 52 in which the stub shafts 4| and 43 are respectively mounted. These bearings position the rotors so that no contact can take place between them and the ends of the casing. The casing 3| is provided with an intake chamber 53 with which an intake passage 54 provided with suitable strainer or other devices, not shown, for preventing the ingress of harmful material, communicates, and the intake space communicates with the right hand, low pressure ends of the rotors, and also for a substantial part of the length of the rotors communicates with the back portions thereof so-to-speak, the portions at the opposite sides of the plane which includes the rotor axes, from the discharge. The casing 3| is provided with a discharge chamber 55 at the left hand (high pressure) end of the rotors, and another chamber 56, whose purpose will later be described, communicates with the chamber 55 though it is separated therefrom for a substantial distance by a web 51.

For the purpose of maintaining the rotors out of contact with each other they are connected by intermeshing helical gears 83 and BI, the gear 63 being splined, as at 82, to the stub shaft 4|, and the gear 8| being splined, as at 83, to the stub shaft 43. The gears 33 and SI are so formed that their helix angles correspond in hand and lead to the helix angles of the rotors to which they are respectively fixed. Regardless of the speed at which the rotors turn, these gears operate to maintain the space packing heretofore referred to; in other words, a very small clearance between the surfaces of the lobes and the sides and bottoms of the grooves of the rotors is maintained, thus preventing wear and permitting the operation of the pump at a speed far exceeding any permissible with rotors running in contact with each other. By reason of the smallness of the clearance maintained and the high speeds of rotation, serious leakage is prevented.

The feature of meshing rotors held out of contact by helical gears of the same hand and lead as the rotors is claimed in my copending application, Serial No. 623,485, filed October 20, 1945. A drive shaft 13, preferably driven through a flexible non-back-lash.drive such as, for example, that disclosed in my application Serial No. 443,414, filed May 18, 1342, now abandoned,

is arranged in alinement with the stub shaft 43 and has a driving connection therewith as shown at 1|. The drive shaft is iournaled by means of a ball bearing 12 carried by the plural-part head 53 and engaging a cylindrical portion 13 on the drive'shaft. Its other end is rotatably supported as later described. Surrounding a cylindrical hub portion 13 of the gear BI is a bearing sleeve 33, and a cylindrical portion 3| at the right hand end of the drive shaft 13 rotatably surrounds the bearing sleeve and is journaled thereon. Keyed to the periphery of the cylindrical portion 8| of the drive shaft is a member 82 having a number of recesses 33 formed therein receiving rollers 84 which are operative, as later described, at times to effect a clutching between the number 82 and a cylindrically bored liner ring 33 keyed, as at 81, to the gear 8|. relatively straight base surfaces 33 and radial surfaces 3|. Through the latter surfaces there project spring-pressed plungers 32 adapted to act upon the rollers 34 and cause them to connect the members 32 and 36 upon predetermined relative rotation between the latter members. Springs 33 act against cross pins 34 and move the plungers 32 against the rollers 34. The pins are supported in end closure or plate members 31 and 33, and the rollers have stems 33 loosely received in openings I33 in the plates 31 and 33. These plates 31 and 33 are supported to turn with the member 32. It will be evident, referring to Figs. 24 and 25, that if the member 82 be driven counterclockwise it will, through the rollera 84, be connected to the liner ring 83 and through the latter drive the gear SI and by virtue of the connection of gear 6| to shaft 43 drive the rotor 33, while through the meshing of gear 8| with gear 53 and the mounting of gear 63 on shaft 4|, rotor 32 will also be driven. If the gear 6| be driven counterclockwise at a greater angular rate than the member 32, it will not be connected to that member and may turn freely in the direction mentioned, relative to it.

It will be noted (Fig. 4) that the stub shaft 4| has another shaft I32 connected with it by means of a splined connector element I33 which has an axial bore I34 for reasons later explained. The left-hand end of shaft I32, as viewed in Fig. 4,15 journaled in a ball bearing I36 carried by the plural part head 53, and carries a gear I31 somewhat smaller than the gear 63. A gear I33, somewhat larger than the gear 3|, meshes with the gear I31 and is journaled by a ball bearing I I3 on a cylindrical portion III of the drive shaft 13. It also has a sleeve portion II2, internally splined at H3 and supported by a ball bearing The recesses 83 have M4 on a further cylindrical portion III of the drive shaft I0. Discs II'I connected to the sleeve portion II2 are interleaved with other discs II8 connected by splines "8 to the drive shaft I0,

which has a flange I20 adjacent the bearing II4 serving as an abutment for the end one of the interleaved series of discs H1, H8 when these are pressed together to connect the gear I08 to the drive shaft I0. A follower member I22 is slidabl supported on a packing ring I23 mounted on the shaft I and has an annular outer sleeve portion I24 with whosebore a peripherally packed plate I25 coacts'to form a chamber I26 for clutch applying hydraulic pressure. A ring I27 seated in an internal groove in the sleeve portion l24 provides an abutment for a flexed annular spring I28 whose opposite side presses upon the side of the plate I25, and the spring I28 normally maintains the follower membar 522 in clutch unloading position.

It may now be noted that when the clutch is loaded, the gear I08 will be connected directly to the shaft 70 and will drive the gear I01 and so the gears 60 and 6 I, and thus the rotors 32 and 35; and because the gear 6| will then be rotated faster than the member 82, and in the same direction with the latter, there will simply be an overrunning clutch action and no tendency for' connection between gear GI and member 82.

It will be evident from what has been said that the drive shaft I0 is rotated counterclockwise in Fig. 2 and that the rotors 33 and 33' turn clockwise in Figs. 29 and 30 while the rotors 32 and 32' turn counterclockwise in the same figures, and

. that air taken in through the intake connection 58 is entrapped between the casing and the rotors and is progressively moved, and if it remains entrapped, compressed as it is moved to the discharge connection 55.

The compressor has automatic means foreffecting change in the manner (and accordingly in the speed) of drive thereof governed by a speed responsive device and it hasautomatic means for effecting the initiation of compressive action thereby governed by the pressure of the air surrounding the airplane. Both of these automatic means are hydraulically operated, so, havin described the hydraulic clutch operating means which efiects high speed drive of the compressor, I shall briefly describe the hydraulically controlled means for initiating compressive action, and then describe'the hydraulic system and its controls which effect the operation of the clutch and the unloading means.

Referring particularly now to Figs. 6, 28 and 29, it will be observed that the casing 3| at the intake side does not fit at all closely to the peripheries of the rotors, but that there are wall portions respectively marked I32 and I33 which except for clearance adequate to constitute space packing do conform 0r fit quite closely to the cylinders traced by the outermost portions of the rotors and that these portions I32 and I33 intersect along a line 134 parallel to the rotor axes. Now, the fluid which is sealed in the successive progressively diminishing chambers between the rotors and the casing walls would be substantially compressed if no escape or discharge were provided until the chamber 55 was reached; and under certain conditions such compression is very desirable. But under other circumstances it is better to avoid material compression and thus conserve power and avoid unnecessary heat-' ing of the cabin. Accordingly, I have provided an opening at I35 so related to the length of the.

casing and the helix angle of the rotors that when the opening I35 is unobstructed no compression of the fluid enclosed between the rotors 32 and 33 will take place before communication with the opening I35 is had;. and therelationship of the opening I35 to the discharge passage 55 is such that the air remaining in the pockets in the rotors as these pockets move out of communication with the opening I35 will not be compressed before these same pockets communicate with the discharge 55.

To control the opening I35, which has a peripheral wall which lies in the surface of a cone, I have provided a valve I36 whose shape is such that when the same is closed it conforms very closely to the walls I32 and I33, as may be seen in Fig. 9. This valve has ears I31 through which pins I38 pass, and these pins are secured in the arms or flanges I39 carried upon a pivotal support member I40 which is secured, by a pivot pin I, to the wall of the casing 3I. A shoulder I42 on the valve and a shoulder I43 on the casing limit the closing movement of the valve I35 to a position in which the walls of said valve conform exactly to the surfaces of the rotor chambers. This valve is adapted normally to be maintained open by a spring I45 engaging at one end the wall of a member. I46 which forms a portion of the enclosure of the discharge chamber 55 and which is secured, in any suitable manner, to the casing 6|. The other end of the spring acts against a piston I41 having a packing I48 fitting the walls of a cylindrical chamber I49 which is formed in a cylinder-providing member I50 also secured, in any suitable manner, to the casing 3| in a position overlying the member I46. A piston rod or operating stem I52 with an enlongated eye connection or passage I56 under a control hereinafter described, and a leakage port I58, shown in Fig.10, is provided to conduct any liquid which may escape past the packing I48 to an oil sump I60 in the lower part of the casing 3|. When the servo-motor I is not under pressure delivered through the passage I56, thevalve I 35 may be moved to the open position shown in Fig. 7 by the spring I45, and in that inclined position it will offer very little obstruction to the discharge of fluid to the chamber 56 and thence to the interior of the cabin through any appropriate connection. When, however, pressure is supplied under certain predetermined conditions to the servomotor I55, the piston I4'I will be caused, through the operating stem I52 and the pin I 54, to close the valve I36, and the compressor will then operate substantially precisely as though there were no opening I35 available. Thus depending upon the position of the valve I36, there is provided by the single unit in effect a mere displacement pump and a compressor capable of substantial compression of air taken in. That this compression may be in practice from one very substantially subatmospheric pressure to a higher one which is itself less than atmospheric does not, of course, alter the fact that there is a definite compression.

The features of a compressor provided with an of operation of the compressor and the loading and unloading are both hydraulically controlled, and I shall now describe the hydraulic system. There is provided in the base of the casing 3| the sump I60. This sump is disposed between the lower wall of .the rotor housing and an outer wall I6I iorming an integral part of the casing 3|. The chamber is, in the horizontal position of the compressor, substantially horizontal, and a pump of the intermeshing gear type is positioned at the right-hand end of the casing as the same is viewed in Fig. 4, so that it is partially submerged and so that its intake is always submerged (in the horizontal position of the casing) in the oil in the sump. This pump, designated I62, includes a casing I63 having intersecting rotor chambers I64 therein in which are rotors I 65 having intermeshing teeth I66 arranged at a slight angle to elements of the cylindrical surface in which the outermost points in the rotor teeth lie. An intake passage I61 conducts oil to the lower sides of the rotors I65, and the oil is carried around by the teeth I66 and is discharged to a discharge space I68 above the plane of the mesh line of the rotors I65. One of the rotors I65 drives the other, and the first mentioned rotor is provided with a shaft I69 which extends through a ported cover plate by a pinion I15 formed integral with the stub shaft 42 and arranged at the extreme righthand end of the latter in Fig. 4. A clean-out plug I16 is arranged below the oil, pump in the bottom of the sump. The discharge passage I68 communicates with passages I18 in the cover I10, and I19 in a supplemental cover, and opens into the bore I80 of the sleeve member I13 previously described. From this latter the fluid is discharged through branch passages IBI- into a chamber I82 containing a strainer structure I83. Between the ends of the chamber I82 and suitably associated with the strainer is an annular peripheral member having a peripheral groove I84 to which the strained lubricant obtains access through radial ports I85. The annular groove I84 communicates with a passage I86 which opens into, an annular groove I81 surrounding the bearing bushing 45. The opposite Side of the annular groove I81 opens into a passage I88 whose upper end opens into a chamber I89. The chamber I89 constitutes a distribution point for oil for lubricating purposes and for operating the speed-changing clutch mechanism previously described and also 'for fluid for closiing the valve I36 previouslyl mentioned. In line with the passage I88 there is another passage I90 opening outwardly and upwardly from the chamber I89. This communicates with an annular groove I92 in the bushing 44. The annular groove has continuously in communication with it obliquely disposed passages I93 opening into a chamber I94 in the stub shaft 40. The chamber I94 is connected by a tube I95 suitably centered as at I96 within the rotor 32, and at the left-hand margin of Fig. 4 the tube I95 opens into a chamber I91 in the stub shaft 4|. As will be apparent from what has been previously described, the chamber I91 communicates through the passage I04 with a hollow interior I 98 of the shaft I02 and discharges through the left-hand end of the latter, as shown in Fig. 4, into a chamber I 10 I99 formed in the multipart head structure 50. Fluid is delivered from the chamber I99 through a lubricant tube 200 into a chamber 20 I between the rotor casing and the chamber I99 and which forms an enclosure for the motor driving gear earlier described. The lubricant tube 200 has two discharge orifices 202 and 203 which respectively discharge lubricant onto the peripheral surfaces of the couples I01, I08 and 60, 6I, thereby keeping the gear couples 60, 6| and I01, I 08 adequately lubricated. The lubricant, after its discharge over these gears, passes downwardly within the chamber 20I and is conducted out of the casing through a passage 205 and a tube 206 of small diameter opening through the side wall of a larger tube 201 back into the sump I60. Lubricant is also discharged directly through the tube 201 back into the sump I60. The presence of the branch tube 206 of small diameter prevents all of the lubricant in the sump I60 from flowing into the chamber 20I when the airplane has occasion to make a dive and interfering with the operation of the driving mechanism for the rotors. Another drain plug 208 is arranged in a position to permit the draining of lubricant from the chamber 20I.

It will be noted that in the stub shaft 40 there is, at the right-hand end of the chamber I94, a partition 2I0 to the right of which there is a valve-receiving bore 2. Other obliquely extending passages 2I2 connect the annular grooves I92 withthe bore 2 at points near the partition 2I0, and a further annular passage 2I3 formed in the bushing 44 is connected with the interior of the bore 2I I by radial passages 2I4. Suitably supported on the rear end of the stub shaft 40 is a mounting 2| 5 for a speedresponsive governor 2I6 which serve in con junction with a spring 2I1 housed in the interior of a valve member 2I8, to vary the position of that valve member in the bore 2I I. The valve member will be observed to be open from end to end, as at 220, and to house the spring 2I1 within it in such a manner that the spring acts on the right-hand end of the valve in Fig. 14 at one end and at its other end acts on the partition or wall 2I0. The valve has a left-hand end collar 222, another annular peripheral collar 223 spaced by a groove 224 from the collar 222 and a further enlarged collar-right-hand portion 225spaced by a peripheral groove, 226 of substantial length from the collar portion 223. The support member 2I5 has a portion 221 guidingly engaging the head 225 and is traversed by openings 228 so that in certain positions of the valve 2I8 there may be a discharge into a chamber 230 at the right-hand end of the compressor, of fluid entering the chamber 2 through the radial passages 2I4.

The governor support 2I6 includes fly weights 232 pivotally supported on transverse pins 233 in earlike portions 234 carried by the support 2I5. Portions 235 of the fly weights at the opposite side of the pivots thereof from the main masses of said fly weights carry adjustable screw devices 236 which have heads 231 adapted to engage the end surface of the head 225, and upon the attainment of the shaft 40 to a predetermined speed of rotation the fly weights actuate the portions 236 to move the valve 2I8 to shift the valve from the position shown in Fig. 14 to that shown in Fig. 16, thereby allowing fluid entering the bore 2I I through the radial passages 2I4 to be vented while at the same time preventing any delivery of fluid from the pump to the radial in which the element 26I is movable.

passages 2I4. The cutting off of the supply of fluid to the radial passages 2I4, and the venting of fluid from these passages through the bore 2| I will efiect, as shortly described, a reduction in the speed of the rotors. This reduction in speed, however, will not be sufiicient to effect an operation of the speed governor permitting the valve to move again to a position for supplying fluid to the passages 2M, as the design of the governor is such that it becomes operative to force the valve US to the left only upon the attainment of a speed as of the order of 7000 R. P. M., while after once assuming the position of Fig. 16 a falling off of the speed to a lower speed of the order of 4000 R. P. M. will be necessary before the weights will be moved in and permit the reestablishment of fluid delivery to the chamber I26 of the hydraulically operated clutch mechanism.

The circumferential groove 2I3 is connected below the stub shaft 40 with a passage 24I which extends downwardly parallel to the axis of the passage I90 and'opens through an opening 242 into the interior of the bore of a valve-receiving bushing 243. This valve-receiving bushing contains a rotatable valve 244, which is used primarily for testing purposes and which has an operating handle 245 by means of which the valve may be turned into any one of three different positions. .In the position of the valve 244, shown in Fig. 4 and in Fig. 11, a diametric passage 246 connects the opening 242 with an op: posite opening 241 in the valve sleeve and via the latter opening to the passage 248 which is connected through a port 249 in the bearing sleeve 41 and anannular groove 250 and radial pas sages 25I with a chamber 252 Within the interior of the stub shaft 42. The outer end ofthis chamber 252 is closed by a plug 253, while the other end of the chamber 252 is connected by a suitably centered tube 255 with arrangements for effecting the operation of the clutch mecha-. nism previously described and for the performance of certain lubricating functions. Before proceeding with the description of this mechanism, it may be pointed out that the valve 2I8 at speeds of the rotor 32 below a predetermined number of R. P. M. will be in the position shown in Figs. 4 and 14 and will connect the pump dis-; charge through the ports and passages previously described with the tube 255,-but that at speeds above such a predetermined number of R. P. M. the valve 2I8 will assume the position shown in Fig. 16 and cut oil communication completely between the passages I90 and 24I and to vent 24I back to the sump through the chamber 230. Now it will be observed, referring particularly to Fig. 4, that at the rear end of the tube 255 there is a bell or funnel shaped member 251 fitting the bore 258 of the stub shaft 43,-and that -a split spring' ring 259 operates to prevent possible movement of the member 251 out of the bore in the stub shaft if any loosening should occur. Within a stepped bore 260 within the drive shaft there is arranged a hollow plunger member 26I which is provided at one end with a perforated flange 262 adapted to seat against a split j ring 263 secured Within. the inner wall of the drive shaft 10. The plunger member 26I is engaged by a spring 264 which reacts against a 1 shoulder 265 within the drive shaft, and a thimble 266 closes the left-hand end of the chamber withterior of the chamber communicates, through obliquely radially extending passages 281, with The in Other radially obliquely extending passages 268 connect the interior of the stepped bore .260 at the right-hand end of the plunger member 26I in communication with the chamber I26.

The mode of operation of the mechanism which has just been described is as follows: When the compressor is started, a driving connection is immediately established between the shaft 10 and the gear Bland the pump I62 commences to deliver fluid through the strainer, through the pasage I86, the chamber I69, the passage I90, the oblique passages 2I2, the annular groove 224, the radial passages 2I4, passages 24I, 246, 248, 25I and the tubularconduit 255 to the interior of the member 251 and to the space between that member and the plunger member 26I. The fluid immediately passes through the perforations in the flange 262 and through the radial passages 268 intothe chamber I26 and brings the clutch discs I I1 and H8 into contact with each other. As the oil continues through the tube 255, the member 26l moves to the left compressing the spring 264, and the compression of this spring is so determined that the clutch pressure will be gradually applied as the member 26I moves to the left.. When this member reaches its extreme left-hand position, the clutch discs may be firmly pressed against each other and drive of the rotors at the higher speed, when the gear I06 is the driving element, will be efiected. It will be appreciated that this high speed driving will be continued until the speed of the compressor builds up to such a degree that the valve 2l8 will be shifted by the governor, and then the slower speed drive between the shaft 10 and the compressor will be, initiated. It will be noted that lubricant will be supplied from the space between the member 26I and the member 251 to the splines.

The feature of the control means for the clutch comprising disks II I and H8 is claimed in my copending application Serial No. 80,844, filed March 11, 1949.

The manually operable valve 244 previously mentioned can be adjusted as previously described to such a position as to restore high speed drive of the compressor aftersuch high speed drive has been automatically interrupted, or to prevent interruption of high speed drive upon the attainment of the predetermined speed of operation at which a shift to low speed drive is normally effected. Furthermore, in another position of adjustment, this valve may be so op erated as to preclude the high speed drive com pletely. It will be noted that in addition to the diametric passage 246 formed in the valve there is a. longitudinal peripheral passage 210 which opens into the space 2 at the right-hand side of the valve, a space which is connected by a passage 212 (Fig. 4) with the chamber 230 which communicates with the sump. When the valve 244 is turned to bring the passage 210 into communication with the passage 248 and to blank off the port 242 with the cylindrical portion of the valve opposite the groove 210, it will be evidently impossible to transmit pressure through the tube 255 for effecting high speed drive of the compressor. The valve 244 also has an oppositely extending longitudinal peripheral groove 214 opening through its end which mm a portion of the bounding wall of the chamber I89. When the valve is turned so as to bring the passage 214 into communication with the passa e 248, fluid will be supplied from the chamber I89 continuously to the passage 248 and the tube 255 and high speed drive of the compressor will alone be possible. Referring to Figs. 3 and 4, it will be apparent that means is provided for locking the handle 245 of the valve 244 either in mid position where the drive of the compressor is controlled by its speed automatically by the speed governor or in either of the other two positions mentioned.- v

' The chamber I89 has a laterally extending passage 216 communicating with the same. Th s passage is adapted to be connected by a longitudinally extending passage 211 under the control of a spring loaded valve 218 'with a passage 219 opening into an annular chamber 280 which surrounds the sleeve 243 and which is connected at its opposite side with a passage 28 I. The function of the spring loaded valve 218 is to maintaina suflicient pressure in the chamber I89 under all circumstances when the compressor is running to insure the operation of the speed change mechanism. The passage 28I has a bore 282 communicating with it, and a valve 283 reciprocates in the bore. A side vent 284 opens out of the bore and leads into the space 230, and a spring 285 having an adjustable follower 286 is adapted to control the pressure in the passage 28 I. The passage 28I communicates through a port 288 with a bore 289 of a valve seat member 29!! mounted in a passage 29I which is connected by another passage 292 to the passage I56 leading to the chamber I55 to which fluid is supplied to actuate the valve I36. It will be evident that if through-escape from the bore 289 is prevented fluid will be supplied to the servo-motor I55 at a pressure determined by the valve 283 and that again, subject to the same condition, the valve I36 would be closed whenever the pump I62 was being driven. However, means is provided whereby the pressure is vented freely from the bore 289 back to the sump at all times when the airplane is operating at levels where the external pressure is above a predetermined amount. It will be observed that the valve seat member 290 is provided with a plurality of ports 294 opening through a surface surrounded by an annular valve seat 295 and that there is further provided a central guide extension 296. Reciprocably mounted upon this guide extension is a valve element 291. As is best seen in Figs. 19 and 20, the movement of this valve element in an opening direction is limited by a'sleeve portion 298 formed on athreaded sleeve member 299 which is supported in a further sleeve mounting element 300 carried by a wall of the casing 3I. An adjustable closure element and spring tension regulator 30*I engages a spring 302 which acts upon the valve 291 and normally tends to seat it. Connected to the valve 291 and to the sleeve member 299 at opposite sides of the sleeve portion 298 are bellows devices 303 and 304 bounding a chamber 305 in which the sleeve 298 is enclosed, and this sleeve is perforated so that free communication may at all times exist throughout the interior of this chamber. The chamber 305 is evacuated, and the compression of the spring 302 is so determined that until the pressure acting upon the exterior of the bellows arrangement falls to a predetermined low value,

the valve 291 will be held firmly open against the stop sleeve 298. When, however, 'the pressure in the casing 300 falls below a predetermined value, the valve 291 will promptly seat and interrupt the discharge of fluid back to the sump and cause the building up of such' a pressure in the chamber I55 as to close the valve I36 and cause the compressor to operate as a compressor in stead of a displacement means. It will be noted that the walls of the casing 300 are perforated as at 309, 3I0 to permit the fluid passing through the passages 294 to flow freely to the sump through the chamber 230. The chamber 230 is connected to external pressure-pressure outside the cabinthrough a pressure device of any suitable construction as shown at 3| I, and a similar device, 3II', connects the chamber 20I to atmosphere. Thus the casing 300 serves as a vent line to atmosphere, so that opening and closing of the vent line'is efiected according to a terminal pressure condition of the compressor, namely, in this case. the intake pressure. The setting of the spring 302 is such that the valve 291 is normally open at heights of the airplane below 25,000 feet. The valve 291 is of the overbalanced type, being of the sharp opening variety, so that when the valve I36 is to open, it may be permitted to open sharply and cleanly. Extending axially through the guide extension 296 is a passage 3 I 2 through which fluid passes from the bore 289 to the interiors of the sleeve member 299 and the bellows device 304. When the valve 291 is seated, fluid supplied under pressure through the passage 3I2 acts against the outer end of the valve and counteracts the increase in pressure on the inner end of the valve produced by the fluid acting through the ports 294.

It will be noted that the rotor 33 is hollow from end to end and that passages 3 I3, 3 connect the space surrounding the left-hand stub shafts H, 43 with the interior of the rotor, while passages 3 I 5 extend through the stub shaft 42, so that any tendency of lubricant to enter the rotor spaces is prevented by pressure equalization. The casing .3I has cooling fins 3 I 6.

An extended summary of the mode of operation of the illustrative embodiment and modification of the invention which have now been described in detail is not necessary in view of the explanations given 'of the modes of operation of the component parts. It may be noted, however, that when the airplane takes 011 the compressor will have the valve I36 open and will simply move large quantities of air at take-off conditions into the cabin. The cabin will be provided with suitable automatic vent mechanism. such for example, as that which forms the subject matter of my application Serial No. 443,413, filed May 18, 1942, for Pressure control devices, so that the cabin pressure will not build up objectionably. When the compressor is caused to rotate, it will be started initially at the slower speed, drive being from the drive shaft 10 through the automatic roller clutch mechanism to the As soon as the compressor has operated long enough to produce the necessary oil pressure in the systema thing which occurs almost instantly-the high speed drive of the compressor rotors will be initiated unless the manual control valve 244 should have been moved to prevent thisan unlikely condition as this valve is used mainly for test purposes. Obviously, if a substantial period of idling is desired prior to take off, this valve could be so manipulated so as to prevent the needless displacement ofair by the compressor. As soon as the compressor driving speed attains to a certain predetermined number of R. P. M., the automatic speed governor mechanism will shift the valve 2I8 to substitute the low speed drive for the high speed drive by interrupting the supplyof clutch loading pressure the compressor during flight the low speed drive will be in operation. The nature of the governor is such as to avoid hunting, and whenthe speed of the compressor is brought up to a value sumcient to initiate low speed drive there will be required a greater reduction in speed than will be occasioned by the change from one drive to the other before the compressor will again shift back to the high speed drive. If the airplane rises to the requisite height so that compression of the air instead of displacement thereof is necessary for satisfactory operation, the evacuated bellows will permit the closing of the valve,

29'l and there will be fluid supplied to the piston ll! of the servo-motor I55, and the valve I36 will be closed and the compressor will then operate to compress the fluid, and all of the fluid taken in will be discharged through the regular discharge passage 55. It will be evident that the compressor will be adequately lubricated at all times and that a pump of the character shown has such capacity for the moving of lubricant that a very efiective delivery of lubricant to the points requiring lubrication will be assured.

As a result of this invention it will be noted that a novel air pump or compressor is provided having novel control mechanism. It will further be evident that by the provision of the novel 'construction and arrangement of parts, an air pump or compressor is provided which is extremely compact and relatively light in weight. It will also be noted that by the novel manner of association of the pump and its control mechanism with the cabin of an airplane it is, through association with automatic vent valve devices such as the one disclosed in application Ser. No. 443,413. possible I automatically to regulate the cabin pressures to .40 externally of the cabin, thereby to enable the accommodate for any changes in air pressures airplane to operate at relatively great heights, or at any lower ones. The novel control features of the invention enable an airplane to operate at high altitudes with safety and with comparative comfort for the cabin occupants and with good economy. Other uses and advantages of the invention will be obvious to those skilled in the art.

While there are in this application specifically described one form and a modification which the invention may assume in practice, it will be un+ derstood that this form and the modification are shown for purposes of illustration and that the invention may be further modified and embodied invarious other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1 In combination, a rotary compressor having a pair of intermeshing rotors, change speed gearin for driving said rotors arranged at one end thereof, a lubricant pump arranged at the other end thereof and driven by one of said rotors, fluid actuated means for controlling said change speed gearing, a governor driven by the other of said rotors, means for delivering lubricant from said pump through one of said rotors to said change speed gearing tov lubricate the latter, and means under the control of said governor for delivering lubricant through the other rotor to said fluid actuated means to cause said change speed gearing to operate with a difierent ratio between its input and output speeds.

2. In combination, a rotary compressor having a pair of intermeshing rotors, change speed gearthereof, a lubricant pump arranged at the other end thereof and driven by one of said rotors, fluid actuated means for controlling said change speed gearing, a governor driven by the other of said rotors, means for delivering lubricant from said pump through the second one of said rotors to said change speed gearing to lubricate the latter, and meansunder the control of said governor for delivering lubricant from said pump through the first rotor to said fluid actuated means to cause said change speed gearing to operate with a (lit-- ferent ratio between its input and output speeds.

3. In combination, a rotary compressor adapted to be operated in widely differently angularly related positions and having a plurality of intermeshing rotors, gearing connected to said rotors including a passage extending axially through one of said rotors for conducting lubricant from said pump to said gearing, and means for conducting lubricant ireely from the space surrounding said gearing to said lubricant chamber when the axes of said rotors lie in horizontal planes and restricting the flow of lubricant from said chamber when said'axes lie in at least some inclined planes.

4. In combination, a, rotary compressor having a pair of intermeshing rotors, change speed gear ing for driving said rotors arranged at one end thereof, a lubricant pump arranged at the other end thereofanddriven by one of said rotors, fluid actuated means for controlling said change speed gearing, a governor driven by the other of said rotors, and rotor-traversin means for delivering lubricant from said pump to said change speed gearing to lubricate the latter, and for delivering lubricant, under the control of said governor, to said fluid actuated means to cause said change speed gearing to operate with a different thereof, alubricant pump driven with said compressor, fluid actuated means for controlling said change speed gearing, a governor driven with said compressor, and rotor-traversing means for de-'.

livering lubricant from said pump to said change speed gearing to lubricate the latter,-and-for dellveringlubricant, under the control of said governor, to said fluid actuated means to cause said change speed gearing to operate with a different ratio between its input and output speeds.

6. In combination, a rotary compressor adapted to be operated in widely differently angularly related positions and having a plurality of intermeshing rotors, gearing at one end of said compressor for driving the same, meansfor lubricatin said gearing including a lubricant chamber, means for pumping lubricant from said chamber, means for conducting lubricant from said pump to said gearing, and means for conducting lubricant freely from the area of said gearing to said lubricant chamber when the axesof said rotors lie in horizontal planes and restricting, the flow of lubricant from said chamber when said axes lie in at least some inclined planes.

WIN w. PAGET.

(References on following page) REFERENCES CITED The following references are of record in the tile of this patent:

UNITED STATES PA'I'ENTS 5 Number Name Date 397,337 Bullard Feb. 5, 1339 1 1,177,898 Rimmer Apr. 4, 1916 1,291,375 Herr Jan. 21, 1919 1,669,050 Grant May 8, 192a 1,686,505 Stastny Oct. 2, 1928 1,878,224 Woolson Sept. 20, 1932 1,954,436 .Waseige Apr. 10, 1934 2,020,987 Ayres Nov. 12, 1935 2,044,867 Woodard June 23, 1936 15 Number Number Name Date Lysholm et a1 Mar. 22, 1938 Lysholm Oct. 3, 1939 Heinrich et a1. Mar. 19, 1940 Horton Feb. 4, 1941 Halford et a]. May 19, 1942 Nallinger Sept. 29, 1942 Woods et a! Jan. 5, 1943 Jacobsson Mar. 9, 1943 Patez Mar. 9, 1943 FOREIGN PATENTS Country Date France Feb. 23, 1914 France Jan. 9, 1930 Certificate of Correction Patent No. 2,477,002 July 26, 1949 WIN W. PAGET It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 4, line 24, for the word seotional read vertical; column 6, line 35, for the word number read member; column 9, line 58, for previouslyl read previously; column 14, line 68, for the words manipulated so as to read manipulated as to;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 20th day of December, A. D. 1949.

THOMAS F. MURPHY,

Aasz'atant Commissioner of Patents. 1' 

